A fuel supply system of the related art described in JP-A-2008-157094 includes a low-pressure fuel supply system configured to supply fuel to a low-pressure fuel capacity chamber (also referred to as a common rail) provided with a low-pressure fuel injection vale through a low-pressure fuel channel by a feed pump (low-pressure fuel supply pump) configured to pump up fuel from a fuel tank and a high-pressure fuel supply system configured to pressurize the fuel pumped up by the feed pump by a high-pressure fuel supply pump and then supply the high-pressure fuel to a high-pressure fuel capacity chamber (also referred to as a high-pressure fuel accumulator) provided with a high-pressure fuel injection valve.
Specifically, the high-pressure fuel supply system includes a bifurcated piping provided at a midpoint of a low-pressure fuel supply piping of the low-pressure fuel supply system, and one piping of the bifurcated piping is connected to the high-pressure fuel pump and the other piping is connected to the low-pressure fuel capacity chamber.